''Grypania'' is an early, tube-shaped fossil from the

Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided i ...

eon. The organism, with a size over one centimeter and consistent form, could have been a giant

bacterium Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

, a bacterial colony, or a

eukaryotic Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

. The oldest probable ''Grypania'' fossils date to about 2100 million years ago (redated from the previous 1870 million)Schneider, D. A., Bickford, M. E., Cannon, W. F., Schulz, K. J., & Hamilton, M. A. (2002)
Age of volcanic rocks and syndepositional iron formations, Marquette Range Supergroup: implications for the tectonic setting of Paleoproterozoic iron formations of the Lake Superior region
Canadian Journal of Earth Sciences, 39(6), 999-1012. and the youngest extended into the

Ediacaran The Ediacaran Period ( ) is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and t ...

period.Wang, Y., Wang, Y., & Du, W. (2016)
The long-ranging macroalga Grypania spiralis from the Ediacaran Doushantuo Formation, Guizhou, South China
Alcheringa: An Australasian Journal of Palaeontology, 1-10. This implies that the time range of this taxon extended for 1200 million years.

References

External links

(scroll down) in "Major Events in the History of Life"
Grypania spiralis photo gallery
specimens from Negaunee Iron Formation, Michigan Proterozoic life Fossil algae Ediacaran life Precambrian fossils Prehistoric life genera {{Eukaryota